Some studies have suggested that insulin resistance and the concomitant compensatory hyperinsulinemia are the underlying pathogenetic mechanism of hypertension in whites. The few studies that have examined this hypothesis in African-Americans have produced conflicting results. Compared to whites, African-Americans have a two fold higher prevalence of hypertension. The mechanisms underlying these racial differences are unclear. The overall purpose of the proposed study is to investigate the relation of insulin levels to hypertension in a bi-racial cohort at high risk of developing hypertension. The importance of preventing hypertension in persons with a high normal blood pressure was emphasized by the recent JNC-V and Primary Prevention of Hypertension reports. We will also explore precursors of higher insulin levels during a 2-hour glucose tolerance test over 6 years of follow-up.